Gastrointestinal infections are a major problem in many humans, and particularly in infant and patients with an impaired immune system or gastrointestinal diseases. The resulting diseases can be life threatening. Gastrointestinal infections are often caused by Escherichia coli, Salmonella, Campylobacter, Porphyromonas gingivalis, Clostridium, Enterobacter and Helicobacter, e.g. Helicobacter pylori. 
Helicobacter pylori (H. pylori) is a Gram-negative, microaerophilic flagellated bacterium that colonizes the gastric mucosa of humans upon infection. H. pylori infection has been associated with severe gastric diseases, such as gastritis, peptic ulcer and gastric cancer. H. pylori has been classified as a Group I carcinogen by the World Health Organisation. H. pylori infection is usually chronic and mostly not heals without specific therapy.
H. pylori infection is mainly acquired in early childhood. Most children are infected during the first 5 years of life. By the age of 10, overall prevalence is more than 75% in developing countries, whereas 10% are infected in developed countries, but prevalence can rise to 30-40% in children from lower socio-economic groups.
With regard to problems of treatment by antibiotics and prophylaxis by vaccination the adhesion, and therefore the infection of H. pylori to the gastric mucosa should be prevented, ideally by dietary oral intervention.
Treatment to eradicate H. pylori infection requires three to four medications with antibiotics. Treatment is very expensive and there is also the risk of increasing antibiotic resistance in bacterial strains and re-infection following unsuccessful therapy. Treatment of children may be the most cost effective method of reducing the incidence of infection and the morbidity and mortality associated with H. pylori related diseases. So far there are no guidelines on the need to treat children. A human vaccine is not yet available. Prophylaxis and therapeutic vaccination have been successful in animal models, but the translation to a human vaccine remains difficult, in part because the immunology of the stomach is still poorly understood.
With regard to the problems of treatment by antibiotics and prophylaxis by vaccination, the adhesion of H. pylori to the gastric mucosa should be prevented. Without adhesion of the bacteria, the risk of a related inflammation resulting in gastritis or possibly in cancer can be minimised. Dietary modulation has proven to be useful in supporting H. pylori infection treatment or prophylaxis in vivo and in vitro
EP 1178104 relates to a nutritional composition comprising a specific essential oil and/or specific pure compound isolated from the essential oil for prevention or treatment of infection by a Helicobacter-like organism. The nutritional composition may also contain a source of carbohydrates, a source of fat and/or a source of a dietary protein, pea protein being one of them.
JP 2005255679 describes a polypeptide obtained by treating butter milk with a protease having not only adhesion inhibitory effect of Helicobacter pylori to gastric mucosa but also the effect of debonding Helicobacter pylori off the gastric mucosa of Helicobacter pylori carriers.
JP 2001335504 describes a proliferation inhibitor of Helicobacter pylori that comprises a soybean protein enzymic hydrolysate as an active ingredient.
WO 2008/043424 discloses a composition for the treatment and/or prevention of infection by gastrointestinal pathogens, in particular Helicobacter pylori and/or a disease associated with infection by said gastrointestinal pathogen in mammals. The composition comprises a pea protein hydrolysate, intact pea protein and/or camel milk protein hydrolysate. A pea protein hydrolysate obtained by hydrolysis by chymotrypsin and trypsin is disclosed.
DE 10317935 describes the use of casein to prepare a composition for prevention or treatment of Helicobacter infection and for preventing diseases caused by Helicobacter infection.